Oil burner extension for furnaces



Nov. 16, 1943. c. E. FISHER OIL BURNER EXTENSION FOR FURNACES Filed Jan. 29, 1941 BY W ATTOR Y5 Patented Nov. 16, 19413 .3 g

Charles -E. Fisher, Titusville, Pa., assignor' to Struthers Wells-Titusville Corporation, Titus-. ville, Pa., a corporation of Maryland Application January 29, 1941, Serial No. 376,517

e p lClaimr (c1. 153-15) This invention relates to an oil burner extension or attachment for usein .connection with the furnaces or fire boxes of water boilers and similar heating devices. 1

Apparatus of this character, as heretofore convstructed, have been found unsatisfactory be- 7 cause the flame of the oil burner and the supply of air thereto was not controlled sufficiently to prevent the top of the furnace extension from burning out unduly rapidly and also prevent destruction of the means whichguided the, flame jectionable vibration 'and rumbling' noise which was very disagreeable;

The objects of this invention are toprovide an oil burner extension for furnaces which over. comes the above'mentioned difficulties and to accomplish this result'by means which are simple in construction and low in cost of manufacture and which can be readily installed and maintained in operative condition without. undue ex-'- pense.

In the accompanying drawing: 7 Fig. 1 is a front elevation of a satisfactory form of oil burner extension "embodying this invention.

Fig. 2 is a vertical longitudinalsection of the same, on an'enlarged scale, in connection'with a part of a furnace, the section being taken on line 2-2, Fig. 1. v

Fig. 3 is a rear elevation of the oil burner extension when removed from the furnace.

In the following description similar characters of reference indicate like parts'in theseveral figures of the drawing.

This oil burner extension may be used in connection with various forms of furnaces for heating water, air and other liquids and fluids, that shown in Fig.7 2 of thedrawing being an example of one form of furnace in connection-with which-this invention may be used. As. there shown the furnace includes a horizontal longitudinal furnace wall ll] of tubular form which encloses the combustion chamber II and which is arranged within the shell l2 of a boiler and surrounded by the water therein. The front end of the furnace wall l projects forwardly a short distance beyond the front wall 13 of the shell so as to form an annular collar orflange l4 thereon for use in making a connectionbetween the furnace and invention.

In general this. oil burner extensioncomprises a hood l5 which-has an inlet for'air from the outeratmosphere and communicates with the the oil burner extension of this frontiend of theflfurnace'and a tubularguide l6 whichis'arranged in th'ehoodso as to form-an outerannular airdistributing conduit l1 between the same and the hood and opens intothe furnace and an inner flame passage I 8Qwhich receives part of the flame; from an oil burner 19 and directs the same rearwardly into the combustion chamber of the furnace.-

The hood is, constructed mainly of sheet steel or the like and comprises longitudinal wall having two laterally spaced upright sides 20 and a curved top 2l.. connecting' the upper ends of the sidesilil, an upright transverse front wall 22 connectedwith the front end of the longitudinal wall, an upright transverse rear wall 23 connected with the lower-edges of the upright parts 20 of the side wall and a horizontal tubular neck 24 connected at'its front'zend with the upper parts of the rear edge of the side wall and projecting horizontally rearward therefrom.' The sidewall, rear wall and neck of the hood; are preferably connected permanently by welding or otherwise but the front wall 22, is detachably connected with the sidewall of the hood this being preferably accomplished by a plurality of ,horizontal bolts 25' secured at their rear ends to the front edge of the side wall and projecting forwardly through the marginal part of the front wall 22,

and thumb nuts 26 applied to the bolts 25 and bearing against the outer'side of the front-wall 22. The lower end parts of the side wall, front wall and rear wall form between'them a vertical air inletpassage 21. which opens at its lower end to the outer atmosphere while its upper end communicates'with the lower part of the air conduit ll. g I

While the oil,,burner extension is in use its neck 24 projects into the collar l4 and, if desired; a tight joint maybe formed'therebetween by a packing, such as cement. The oil burner extension may be supported in any suitable manner but preferably by means of legs 29 secured to the lower parts thereof and resting on the floor of the building, as shown in the drawing.

The amount of air supplied to the hood through the lower inlet 21 may be controlled by various.

damper more or lessQsuch as an automatic temperature control apparatus having a chain 32 connected with an eye 33 on the front edge'of the damper and adapted to raise and lower the latter in response to changes in temperature of the room or space which is being heated.

In practice the front edge of the damper is provided with several eyes 33which may be temporarily connected byxmeans of bolts' 34 or the like with similar eyes 35 on the lower edge of the front wall, as shown by dotted lines in Fig. 1 and g thereby retain the damper in closed position and prevent the same from being? dama ed-during 1 transportation as well as stored compactly.

In its central part and axi'ally* in line with the collar 24 the front wall of the" hood is. provided with a burner opening 36 through which the nose or delivery end of the oil burneif I projects rearwardly. This burner which is supplied with fuel oil and primary air to producea combustible mixture may be of any usuali and well known construction and delivers. a:-spray of rearwardlyfiaring conical form? into the cornbustion chamber of 'the furnace, as shown by dotted: lines'3lp- Thetubular-guidecontrolsthe'diredticn' alflcwof the 'sec'ondary' air which is supplied through the secondary air inlet 21 'relative toithe flame of the oil burner and has the general form of a hollow cone which is arranged'centrally within" the neck 24 and the adjacent upper part of' thehood andforms withthe latter the: air conduit 11 which is of annular" form and has its lower. part in" communication with the inlet 21' so r as: to receive a secondary air supply therefrom, while the rear side of this annular conduit opens=into bustion chamber of the boiler. In the preferred construction of the refractory lining shown in Fig. 2 the wall of the same iscoin'paratively thick at its" front end and relatively thin at its rear end thereby rendering the air g'uid'e strong and durable and providing a firm and reliable support for the'lining on' the hood; 4 H F Various means may be employed for securely attaching the lining of the tubular air guide to' the "sheet met'albody of the same but this is preferably accomplished by a' plurality of anchors having the form of headed metal studs the n'arrow shanks 40 of which are secured to the outer metal body 38 ofthe air guide'and inner enlarged heads 4| of which are embedded in the lining while the same is still in plastic form.

Between its front andrear ends the body and lining of the conical air guiding tube is provided with a plurality of air injector openings which are preferably arranged in an annular row and each of which opens at its outer end to the annular air distributing chamber [7 surrounding the air guide while'itsi inner end opens into the centrallongitudinal flame passage within the tubular guide. Theouteripart'fl'of eachof these inj'e'ctor' openings is preferably cut through the" metal bod} 6f the tubular guide while the inner part 43 orthe same is molded in the lining by placing a wooden core 44 in the outer part 42 of the respective injector opening and then applying the plastic refractory material to the inner side of the metal body 38 and around this core and leaving the latter in place until the plastic lining has dried after which the core is removed.

Each of the injector openings in the air guide is preferably inclined so that its axis is at right angles or substantially so relative to the angle of the conical flame issuing from the oil burner. It" will be noted that by making the upper part of the hood ofcylindrical form and the air guide of rearwardly-flaring form that this produces an annular air distributing chamber which is of gradually decreasing cross sectional area from the front end ofthe air guide to the rear end of the same, thereby causing that part of the air which flows directly from the distributing cham- 20' her into the combustion chamber to be retarded and another! part of the air to'fiowfrom thedistrib'uting chamber, through the airi openings '42, 43 in thea-ir guide into the'bore of the lining-3 9 and thus thoroughly aerates the. vaporized fuel and-promote its combustion; V

In theoperation' of this oil burner extension the combustible mixture of fuel oil and primary air flows from the nose'of the burner rearwardly in the'form' of. a conical flame through the air guide and into the'combustion chamber. At the same time air is delivered by the injector openings in the guide from the distributing conduit tothe periphery'of the conical flame beforethe latter issues from the rear end of-the conical guide andthereby further aerates the flame and increases its' combustibility and heat: producing capacity. 'As' the" flame issues from= the conical guide another stream of air of annular form is supplied to the periphery ofthe flame, which stream completely encloses the flame so'that the air reaches all'parts thereof and produces acombusti'ble mixturewhich yields the maximum heat units;

By thus'delivering secondary air to the flame in the form of an annular stream the latter also operates to protect the metal of the air guide against excessive heating by the flame and also protects the adjacent metal parts of the hood from being burned out by the flame and instead causes this flame to expend its heat within the combustion chamber of the boiler, thereby utilizing" the fuel 011 more advantageously and economically and saving the'parts of the oil burner extension from the destructive effects of this flame.

If desired the lower partof the inner side of the combustion chamber may be provided with a protecting mat 45 of fire brick which is heated by the flame, whereby any combustible particles that are not projected far enough into the combustion chamber by the oil burner will drop on this mat and" be gasifledthereby and thus insure coLplete'consumption thereof in the combustion chamber.

This improved oil burner extension protects the so-called d'ry' end of front end of the boiler from injury or burning outinasmuch as the conical guide extends rearwardly beyond the dry end (if the combustion chamber H and more fully into" the SO -Called Wet part of this chamber.

This form of the extension also prevents itshood from'bein'g burned out inasmuch as the-sec ondary air forms a protecting body of annular or ring form between the central cone" and the surrounding parts of the hood from the front side of the latter to the rear end of the cone.

By supplying air in the form of an annular or ring-shaped stream, the air is fed to the entire circumference of the flame and thus tends constantly to maintain the flame in round form while moving through the combustion chamber instead 7 of permitting the flame to become turbulent and engage the wall of the combustion chamber in less efiicient form.

Maintaining the flame in circular form has the further advantage in that this has a tendency to reduce vibration as compared with other formsof oil burner extensions in which the air is taken from the side of the extension and thus tends to throw the combustible stream laterally against the side wall of the combustion chamber and due to the vacuum created causes the air stream to strike the sides of the combustion chamber and which surrounds the combustible stream and prevents any vibration of the same. I r

In the preferred construction of this apparatus the upper part of the'front wall 22 of the hood is provided with a peep hole 46 in order to enable the attendant to observe the operation of the apparatus from the exterior of the same.

I claim as my invention:

.An oil burning apparatus comprising a hood having a lower part provided with an air inlet and an upper part which communicates with said lower part and is provided with a front burner opening adapted to receive an oilburner and a rear air outlet, and a tube arranged in the upper part of said hood coaxially with said burner opening and air outlet and extending rearwardly beyond the rear side of said hood, said tube being of rearwardly flaring form and producing with the upper part of said hood an outer air passage which is of annular form and is of gradually decreasing cross section 'frOm the front side to the rear side'of the hood and said outer air passage having its rear end open around said tube, and said tube also forming an inner air passage which is off conical form and enlarges from the front side of the hood beyond the rear'side of the same.

CHARLES E. FISHER. 

